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Manual Chapter: Configuring Monitors
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An important feature of the BIG-IP® local traffic management system is a load-balancing tool called monitors. Monitors verify connections on pool members or nodes. A monitor can be a health monitor, designed to report the status of a pool, pool member, or node on an ongoing basis, at a set interval. A monitor can also be a performance monitor, designed to report the performance of a node. If a pool member or node being checked does not respond within a specified timeout period, or the status of a node indicates that performance is degraded, the BIG-IP system can redirect the traffic to another pool member or node.
Some monitors are included as part of the BIG-IP system, while other monitors are user-created. Monitors that the BIG-IP system provides are called pre-configured monitors. User-created monitors are called custom monitors. For more information on pre-configured and custom monitors, see Understanding pre-configured and custom monitors.
Before configuring and using monitors, it is helpful to understand some basic concepts regarding monitor types, monitor settings, and monitor implementation.
Monitor types
Every monitor, whether pre-configured or custom, is a certain type of monitor. Each type of monitor checks the status of a particular protocol, service, or application. For example, one type of monitor is HTTP. An HTTP type of monitor allows you to monitor the availability of the HTTP service on a pool, pool member, or node. A WMI type of monitor allows you to monitor the performance of a node that is running the Windows Management Instrumentation (WMI) software. An ICMP type of monitor simply determines whether the status of a node is up or down. For more information on monitor types, see Summary of monitor types, and Special configuration considerations.
Monitor settings
Every monitor consists of settings with values. The settings and their values differ depending on the type of monitor. In some cases, the BIG-IP system assigns default values. For example, Figure 12.1 shows that an ICMP-type monitor has these settings and default values.
Name my_icmp
Type ICMP
Transparent No
Alias Address * All Addresses
The settings in Figure 12.1 specify that an ICMP type of monitor is configured to check the status of an IP address every 5 seconds, and to time out every 16 seconds. The destination IP address that the monitor checks is specified by the Alias Address setting, with the value * All Addresses. Thus, in the preceding example, all IP addresses with which the monitor is associated are checked. For more information on monitor settings, see Special configuration considerations.
Monitor implementation
The task of implementing a monitor varies depending on whether you are using a pre-configured monitor or creating a custom monitor. If you want to implement a pre-configured monitor, you need only associate the monitor with a pool, pool member, or node. If you want to implement a custom monitor, you must first create the custom monitor, and then associate it with a pool, pool member, or node. For more information on implementing a monitor, see Understanding pre-configured and custom monitors, and Creating a custom monitor.
The BIG-IP system includes many different types of monitors, each designed to perform a specific type of monitoring. Table 12.1 lists the monitor types that you can configure for controlling your network traffic.
Verifies the Hypertext Transfer Protocol Secure (HTTPS) service by attempting to receive specific content from a web page protected by Secure Socket Layer (SSL) security.
Verifies the File Transfer Protocol (FTP) service by attempting to download a specific file to the /var/tmp directory on an BIG-IP system. Once downloaded successfully, the file is not saved.
Verifies the Internet Message Access Protocol (IMAP) by attempting to open a specified mail folder on a server. This monitor is similar to the pop3 monitor.
Verifies Microsoft® Windows® SQL-based services.
Verifies services based on Oracle® by attempting to perform an Oracle login to a service.
Checks the current CPU, memory, and disk usage of a node that is running an SNMP data collection agent, and then dynamically load balances traffic accordingly.
Checks the current user usage of a node that is running an SNMP data collection agent, and then dynamically load balances traffic accordingly. The way that you configure the monitor settings determines the data that the BIG-IP system collects.
Checks the performance of a node that is running the Windows Management Infrastructure (WMI) data collection agent and then dynamically load balances traffic accordingly.
When you want to monitor the health or performance of pool members or nodes, you can either use a pre-configured monitor, or create and configure a custom monitor.
For a subset of monitor types, the BIG-IP system includes a set of pre-configured monitors. A pre-configured monitor is an existing monitor that the BIG-IP system provides for you, with its settings already configured. You cannot modify pre-configured monitor settings, as they are intended to be used as is. The purpose of a pre-configured monitor is to eliminate the need for you to explicitly create one. You use a pre-configured monitor when the values of the settings meet your needs as is.
An example of a pre-configured monitor is the icmp monitor. Figure 12.2 shows the icmp monitor, with values configured for its Interval, Timeout, and Alias Address settings. Note that the Interval value is 5, the Timeout value is 16, the Transparent value is No, and the Alias Address value is * All Addresses.
Figure 12.2 The icmp pre-configured monitor
Name icmp
Type ICMP
Interval 5
Transparent No
Alias Address * All Addresses
If the Interval, Timeout, Transparent, and Alias Address values meet your needs, you simply assign the icmp pre-configured monitor directly to a pool, pool member, or node, using the Pools or Nodes screens within the Configuration utility. In this case, you do not need to use the Monitors screens, unless you simply want to view the values of the pre-configured monitor settings.
Important: All pre-configured monitors reside in partition Common. For information on partitions, see the BIG-IP® Network and System Management Guide.
A custom monitor is a monitor that you create based on one of the allowed monitor types.You create a custom monitor when the values defined in a pre-configured monitor do not meet your needs, or no pre-configured monitor exists for the type of monitor you are creating. (For information on monitor types, see Summary of monitor types.)
If a pre-configured monitor exists that corresponds to the type of custom monitor you are creating, you can import the settings and values of that pre-configured monitor into the custom monitor. You are then free to change those setting values to suit your needs. For example, if you create a custom monitor called my_icmp, the monitor can inherit the settings and values of the pre-configured monitor icmp. This ability to import existing setting values is useful when you want to retain some setting values for your new monitor but modify others.
Figure 12.3 shows an example of a custom ICMP-type monitor called my_icmp, which is based on the pre-configured monitor icmp. Note that the Interval value has been changed to 10, and the Timeout value to 20. The other settings retain the values defined in the pre-configured monitor.
Name my_icmp
Type ICMP
Alias Address * All Addresses
You can import settings from another custom monitor instead of from a pre-configured monitor. This is useful when you would rather use the setting values defined in another custom monitor, or when no pre-configured monitor exists for the type of monitor you are creating. For example, if you create a custom monitor called my_oracle_server2, you can import settings from an existing Oracle-type monitor such as my_oracle_server1. In this case, because the BIG-IP system does not provide a pre-configured Oracle-type monitor, a custom monitor is the only kind of monitor from which you can import setting values.
Selecting a monitor is straightforward. Like icmp, each of the monitors has a Type setting based on the type of service it checks, for example, http, https, ftp, pop3, and takes that type as its name. (Exceptions are port-specific monitors, like the external monitor, which calls a user-supplied program.)
If no pre-configured or custom monitor exists that corresponds to the type of monitor you are creating, the BIG-IP system imports settings from a monitor template. A monitor template is a non-visible entity that exists within the BIG-IP system for each monitor type and contains a group of settings and default values. A monitor template merely serves as a tool for the BIG-IP system to use for importing settings to a custom monitor when no monitor of that type already exists.
When you create a custom monitor, you use the Configuration utility to: give the monitor a unique name, specify a monitor type, and, if a monitor of that type already exists, import settings and their values from the existing monitor. You can then change the values of any imported settings.
You must base each custom monitor on a monitor type. When you create a monitor, the Configuration utility displays a list of monitor types. To specify a monitor type, simply choose the one that corresponds to the service you want to check. For example, if you want to want to create a monitor that checks the health of the HTTP service on a pool, you choose HTTP as the monitor type.
If you want to check more than one service on a pool or pool member (for example HTTP and HTTPS), you can associate more than one monitor on that pool or pool member. For more information, see Chapter 4, Configuring Load Balancing Pools.
Checking services is not the only reason for implementing a monitor. If you want to verify only that the destination IP address is alive, or that the path to it through a transparent node is alive, use one of the simple monitors, icmp or tcp_echo. Or, if you want to verify TCP only, use the monitor tcp.
Important: When you create a custom monitor, the BIG-IP system places the monitor into your current administrative partition. For information on partitions, see the BIG-IP® Network and System Management Guide.
1.
On the Main tab, expand Local Traffic, and click Monitors.
The Monitors screen opens.
2.
In the upper right corner of the screen, click Create.
The New Monitor screen opens.
Note: If the Create button is unavailable, this indicates that your user role does not grant you permission to create a custom monitor.
3.
For the Type setting, select the type of monitor that you want to create.
If a monitor of that type already exists, Import Settings appears.
If Import Settings appears, choose a monitor name from the list.
If a monitor of the type you selected does not exist, in the Name box, type a unique name for the custom monitor.
5.
In the Configuration section of the screen, select Advanced. This allows you to modify additional default settings.
7.
Click Finished.
Every pre-configured or custom monitor has settings with some default values assigned. The following sections contain information that is useful when changing these default values.
By default, the value for the Alias Address setting in the monitors is set to the wildcard * Addresses, and the Alias Service Port setting is set to the wildcard * Ports. This value causes the monitor instance created for a pool, pool member, or node to take that nodes address or address and port as its destination. You can, however, replace either or both wildcard symbols with an explicit destination value, by creating a custom monitor. An explicit value for the Alias Address and/or Alias Service Port setting is used to force the instance destination to a specific address and/or port which may not be that of the pool, pool member, or node.
The ECV monitors http, https, and tcp have the settings Send String and Receive String for the send string and receive expression, respectively.
The most common Send String value is GET /, which retrieves a default HTML page for a web site. To retrieve a specific page from a web site, you can enter a Send String value that is a fully qualified path name:
The Receive String expression is the text string the monitor looks for in the returned resource. The most common Receive String expressions contain a text string that is included in a particular HTML page on your site. The text string can be regular text, HTML tags, or image names.
The sample Receive expression below searches for a standard HTML tag:
You can also use the default null Receive String value [""]. In this case, any content retrieved is considered a match. If both the Send String and Receive String are left empty, only a simple connection check is performed.
For HTTP and FTP monitors, you can use the special settings get or hurl in place of Send String and Receive String statements. For FTP monitors specifically, the GET setting specifies the full path to the file to retrieve.
The normal and default behavior for a monitor is to ping the destination pool, pool member, or node by an unspecified route, and to mark the node up if the test is successful. However, with certain monitor types, you can specify a route through which the monitor pings the destination server. You configure this by specifying the Transparent or Reverse setting within a custom monitor.
Transparent setting
Sometimes it is necessary to ping the aliased destination through a transparent pool, pool member, or node. When you create a custom monitor and set the Transparent setting to Yes, the BIG-IP system forces the monitor to ping through the pool, pool member, or node with which it is associated (usually a firewall) to the pool, pool member, or node. (In other words, if there are two firewalls in a load balancing pool, the destination pool, pool member, or node is always pinged through the pool, pool member, or node specified; not through the pool, pool member, or node selected by the load balancing method.) In this way, the transparent pool, pool member, or node is tested: if there is no response, the transparent pool, pool member, or node is marked as down.
Common examples are checking a router, or checking a mail or FTP server through a firewall. For example, you might want to check the router address 10.10.10.53:80 through a transparent firewall 10.10.10.101:80. To do this, you create a monitor called http_trans in which you specify 10.10.10.53:80 as the monitor destination address, and set the Transparent setting to Yes. Then you associate the monitor http_trans with the transparent pool, pool member, or node.
This causes the monitor to check the address 10.10.10 53:80 through 10.10.10.101:80. (In other words, the BIG-IP system routes the check of 10.10.10.53:80 through 10.10.10.101:80.) If the correct response is not received from 10.10.10.53:80, then 10.10.10.101:80 is marked down. For more information on associating monitors with pool members or nodes, see Associating monitors with pools and nodes.
Reverse setting
With the Reverse setting set to Yes, the monitor marks the pool, pool member, or node down when the test is successful. For example, if the content on your web site home page is dynamic and changes frequently, you may want to set up a reverse ECV service check that looks for the string "Error". A match for this string means that the web server was down.
Table 12.2 shows the monitors that contain either the Transparent setting or both the Reverse and Transparent settings.
Table 12.2 Monitors that contain the Transparent or Reverse settings
By default, when a monitor detects that a resource (that is, a node or a pool member) is unavailable, the BIG-IP system marks the resource as down and routes traffic to the next appropriate resource as dictated by the active load balancing method. When the monitor next determines that the resource is available again, the BIG-IP system marks the resource as up and immediately considers the resource to be available for load balancing connection requests. While this process is appropriate for most resources, there are situations where you want to manually designate a resource as available, rather than allow the BIG-IP system to do that automatically. You can manually designate a resource as available by configuring the Manual Resume attribute of the monitor.
For example, consider a monitor that you assigned to a resource to track the availability of an HTML file, index.html, for a web site. During the course of a business day, you decide that you need to restart the system that hosts the web site. The monitor detects the restart action and informs the BIG-IP system that the resource is now unavailable. When the system restarts, the monitor detects that the index.html file is available, and begins sending connection requests to the web site. However, the rest of the web site might not be ready to receive connection requests. Consequently, the BIG-IP system sends connection requests to the web site before the site can respond effectively.
To prevent this problem, you can configure the Manual Resume attribute of the monitor. When you set the Manual Resume attribute to Yes, you ensure that the BIG-IP system considers the resource to be unavailable until you manually enable that resource.
To summarize, if you set the Manual Resume attribute of a monitor to Yes and then associate the monitor with a resource, and the resource subsequently becomes unavailable, the resource remains offline until you manually re-enable it.
You can configure the Manual Resume attribute when you create a custom monitor or you can modify the Manual Resume attribute of an existing custom monitor. For information on creating a custom monitor, see Creating a custom monitor. For information on modifying the Manual Resume attribute of an existing customer monitor, see the following procedure.
1.
On the Main tab of the navigation pane, expand Local Traffic and then click Monitors.
The main monitors screen opens.
2.
Click the name of the appropriate monitor.
The properties screen for the monitor opens.
3.
From the Configuration list, select Advanced.
4.
In the Manual Resume option, click Yes.
5.
Click Update.
If you have a resource (such as a pool member or node) that a monitor marked as down, and the resource has subsequently become available again, you must manually re-enable that resource if the monitors Manual Resume attribute is set to Yes. Manually re-enabling the resource allows the BIG-IP system to resume sending connections to that resource.
The procedure for manually re-enabling a resource varies depending on whether the resource is a pool, a pool member, or a node. For more information, see Chapter 3, Configuring Nodes, and Chapter 4, Configuring Load Balancing Pools.
Once you have created a monitor and configured its settings, the final task is to associate the monitor with the server or servers to be monitored. The server or servers can be either a pool, a pool member, or a node, depending on the monitor type.
Some monitor types are designed for association with nodes only, and not pools or pool members. Other monitor types are intended for association with pools and pool members only, and not nodes. Node-only monitors specify a destination address in the format of an IP address only, with no service port (for example, 10.10.10.2). Conversely, monitors that you can associate with nodes, pools, and pool members specify a destination address in the format of an IP address and service port (for example, 10.10.10.2:80). Therefore, when you use the Configuration utility to associate a monitor with a pool, pool member, or node, the utility displays only those pre-configured monitors that are designed for association with that server. For example, you cannot associate the monitor icmp with a pool or its members, since the icmp monitor is designed to check the status of a node itself and not any service running on that node.
When you associate a monitor with a server, the BIG-IP system automatically creates an instance of that monitor for that server. A monitor association thus creates an instance of a monitor for each server that you specify. Therefore, you can have multiple instances of the same monitor running on your servers.
The Configuration utility allows you to disable an instance of a monitor that is running on a server. This allows you to suspend health or performance checking, without having to actually remove the monitor association. When you are ready to begin monitoring that server again, you simply re-enable that instance of the monitor.
Monitor-to-pool association
This type of association associates a monitor with an entire load balancing pool. In this case, the monitor checks all members of the pool. For example, you can create an instance of the monitor http for every member of the pool my_pool, thus ensuring that all members of that pool are checked.
Monitor-to-pool member association
This type of association associates a monitor with an individual pool member, that is, an IP address and service. In this case, the monitor checks only that pool member and not any other members of the pool. For example, you can create an instance of the monitor http for pool member 10.10.10.10:80 of my_pool.
Monitor-to-node association
This type of association associates a monitor with a specific node. In this case, the monitor checks only the node itself, and not any services running on that node. For example, you can create an instance of the monitor icmp for node 10.10.10.10. In this case, the monitor checks the specific node only, and not any services running on that node.
You can designate a monitor as the default monitor that you want the BIG-IP system to associate with one or more nodes. In this case, any node to which you have not specifically assigned a monitor inherits the default monitor.
For more information on associating monitors with pools and pool members, see Chapter 4, Configuring Load Balancing Pools. For more information on associating monitors with nodes, see Chapter 3, Configuring Nodes.
Simple monitors
These are health monitors that monitor the status of a node.
Extended Content Verification (ECV) monitors
These are health monitors that verify service status by retrieving specific content from pool members or nodes.
External Application Verification (EAV) monitors
These are health or performance monitors that verify service status by executing remote applications, using an external service-checker program.
The BIG-IP system provides a set of pre-configured simple monitors: icmp, gateway_icmp, tcp_echo, and tcp_half_open. You can either use these pre-configured monitors as is, or create custom monitors of these types.
The following sections describe each type of simple monitor and show the pre-configured monitor for each type. Note that each pre-configured monitor consists of settings and their values. The boldfaced type within each pre-configured monitor serves to distinguish the settings from their corresponding values.
Important: When defining values for custom monitors, make sure you avoid using any values that are on the list of reserved keywords. For more information, see solution number 3653 (for 9.0+ systems) on the AskF5sm technical support web site.
Using an ICMP type of monitor, you can use Internet Control Message Protocol (ICMP) to make a simple node check. The check is successful if the monitor receives a response to an ICMP_ECHO datagram. Figure 12.4 shows the settings and their values for the pre-configured monitor icmp.
Figure 12.4 The icmp pre-configured monitor
Name icmp
Type ICMP
Alias Address * All Addresses
The Transparent mode is an option for ICMP-type monitors. When you set this mode to Yes, the monitor pings the node with which the monitor is associated. For more information about Transparent mode, refer to Using transparent and reverse modes.
A Gateway ICMP type of monitor has a special purpose. You use this monitor for a pool that implements gateway failsafe for high availability.
A Gateway ICMP monitor functions the same way as an ICMP monitor, except that you can apply a Gateway ICMP monitor to a pool member. (Remember that you can apply an ICMP monitor to a node only and not a pool member.) Figure 12.5 shows the settings and their values for the pre-configured gateway_icmp monitor.
Figure 12.5 The gateway_icmp pre-configured monitor
Name gateway_icmp
Type Gateway ICMP
Alias Address * All Addresses
Alias Service Port * All Ports
With a TCP Echo type of monitor, you can verify Transmission Control Protocol (TCP) connections. The check is successful if the BIG-IP system receives a response to a TCP Echo message. The TCP Echo type also supports Transparent mode. In this mode, the node with which the monitor is associated is pinged through to the destination node. (For more information about Transparent mode, see Using transparent and reverse modes.)
To use a TCP Echo monitor type, you must ensure that TCP Echo is enabled on the nodes being monitored. Figure 12.6 shows the settings for the pre-configured monitor tcp_echo.
Figure 12.6 The tcp_echo pre-configured monitor
Name tcp_echo
Type TCP Echo
Alias Address * All Addresses
A TCP Half Open type of monitor performs a quick check on the associated service by sending a TCP SYN packet to the service. As soon as the monitor receives the SYN-ACK packet from the service, the monitor considers the service to be in an up state, and sends a RESET to the service instead of completing the three-way handshake.
Figure 12.7 shows the settings for the pre-configured monitor tcp_half_open.
Figure 12.7 The tcp_half_open pre-configured monitor
Name tcp_half_open
Type TCP Half Open
Alias Addresses * All Addresses
ECV monitors use Send String and Receive String settings in an attempt to retrieve explicit content from pool members or nodes. The BIG-IP system provides the pre-configured monitors tcp, http, https, and https_443 for these ECV monitor types:
You can associate TCP, HTTP, and HTTPS monitors with pools and pool members only. You cannot associate them with nodes. You can either use the pre-configured ECV monitors as is, or create custom monitors from these monitor types.
The following sections describe each type of simple monitor and show the pre-configured monitor for each type. Note that each pre-configured monitor consists of settings and their values. The boldfaced type within each pre-configured monitor serves to distinguish the settings from their corresponding values.
Important: When defining values for custom monitors, make sure you avoid using any values that are on the list of reserved keywords. For more information, see solution number 3653 (for 9.0+ systems) on the AskF5sm technical support web site.
A TCP type of monitor attempts to receive specific content sent over TCP. The check is successful when the content matches the Receive String value. A TCP type of monitor takes a Send String value and a Receive String value. If the Send String value is blank and a connection can be made, the service is considered up. A blank Receive String value matches any response. Both Transparent and Reverse modes are options. For more information about Transparent and Reverse modes, see Using transparent and reverse modes.
Figure 12.8 shows the settings for the pre-configured monitor tcp.
Figure 12.8 The tcp pre-configured monitor
Name tcp
Type TCP
Alias Address * All Addresses
Alias Service Port * All Ports
You can use an HTTP type of monitor to check the status of Hypertext Transfer Protocol (HTTP) traffic. Like a TCP monitor, an HTTP monitor attempts to receive specific content from a web page, and unlike a TCP monitor, may send a user name and password. The check is successful when the content matches the Receive String value. Note that you can specify the value of a response header as the Receive String value. For example, the value of the Receive String attribute can be 404 Object Not Found.
An HTTP monitor uses a send string, a receive string, a user name, a password, and optional Reverse and Transparent modes. (If there is no password security, you must use blank strings [""] for the Username and Password settings.)
Figure 12.9 shows the settings of the pre-configured monitor http.
Figure 12.9 The http pre-configured monitor
Name http
Type HTTP
Alias Address * All Addresses
Alias Service Port * All Ports
You use an HTTPS type of monitor to check the status of Hypertext Transfer Protocol Secure (HTTPS) traffic. An HTTPS type of monitor attempts to receive specific content from a web page protected by SSL security. The check is successful when the content matches the Receive String value.
HTTPS-type monitors use Send String, Receive String, User Name, Password attributes, and an optional Reverse setting. (If there is no password security, you must use blank strings [""] for the Username and Password settings.) Note that you can specify the value of a response header as the Receive String value. For example, the value of the Receive String attribute can be 404 Object Not Found.
HTTPS-type monitors also include the settings Cipher List, Compatibility, and Client Certificate. If you do not specify a cipher list, the monitor uses the default cipher list DEFAULT:+SHA:+3DES:+kEDH. When you set the Compatibility setting to Enabled, this sets the SSL options to ALL. You use the Client Certificate setting to specify a certificate file that the monitor then presents to the server.
The BIG-IP system provides two pre-configured HTTPS monitors, https and https_443. Figure 12.10 shows the settings of the pre-configured monitor https, and Figure 12.11 shows the settings of the pre-configured https_443.
Figure 12.10 The https pre-configured monitor
Name https
Type HTTPS
Alias Address * All Addresses
Alias Service Port * All Ports
Figure 12.11 The https_443 pre-configured monitor
Name https_443
Type HTTPS_443
Alias Address * All Addresses
The Reverse and Transparent modes are for monitors that import settings from the https and https_443 monitors. For more information on Reverse and Transparent modes, see Using transparent and reverse modes.
EAV monitors verify applications on servers by running those applications remotely, using an external service checker program located in the directory /usr/bin/monitors.
Important: If you configure a performance monitor, such as the SNMP DCA or WMI monitor type, you should also configure a health monitor. Configuring a health monitor ensures that the BIG-IP system reports accurate node availability status.
The BIG-IP system provides two pre-configured EAV monitors, snmp_dca and real_server, based on the monitor types SNMP DCA and Real Server. For any other EAV monitor type that you want to use, you create a custom monitor.
The following sections describe each type of simple monitor and show the pre-configured monitor for each type. Note that each pre-configured monitor consists of settings and their values. The boldfaced type within each pre-configured monitor serves to distinguish the settings from their corresponding values.
Important: When defining values for custom monitors, avoid using any values that are on the list of reserved keywords. For more information, see solution number 3653 (for 9.0+ systems) on the AskF5SM web site.
Using an External type of monitor, you can create your own monitor type. To do this, you create a custom External-type monitor and within it, specify a user-supplied monitor to run.
It is the External Program setting that you use to specify the executable name of your user-supplied monitor program. An External-type monitor searches the directory /usr/bin/monitors for that monitor name.
The Arguments setting allows you to specify any command-line arguments that are required.
Figure 12.12 shows the settings and default values of an External-type monitor.
Name my_external
Type External
Alias Address * All Addresses
Alias Service Port * All Ports
The purpose of this monitor is to check the health of FirePass systems. Figure 12.13 shows the settings and default values of a FirePass-type monitor
Type External
Cipher List HIGH:!ADH
Alias Address *All Addresses
Name
Specifies a unique name for the custom monitor, such as my_firepass_monitor.
Type
Specifies the type of monitor you are creating.
Interval
Specifies the frequency at which the system issues the monitor check. The default is 5 seconds.
Timeout
Specifies the number of seconds in which the node must respond to the monitor request. The default is 16 seconds. If the node responds within the set time period, the node is considered to be up. If the node does not respond within the set time period, the node is considered to be down. Also, if the node responds with a RESET packet, the system flags the node as down immediately, without waiting for the timeout interval to expire. Note that the Timeout setting should be three times the Interval setting, plus 1 second.
Manual Resume
Using the Manual Resume setting, you can manually designate a resource as being available. For more information, see Chapter 12, Configuring Monitors.
Cipher List
If you do not specify a cipher list, the monitor uses the default cipher list DEFAULT:+SHA:+3DES:+kEDH.
Max Load Average
Specifies the number that the monitor uses to mark the FirePass system up or down. The system compares this setting to a one-minute average of the FirePass system load. When the FirePass system-load average falls within the specified Max Load Average value, the monitor marks the FirePass system up. When the average exceeds the setting, the monitor marks the system down. The default value is 12.0.
Concurrency Limit
Specifies the maximum percentage of licensed connections currently in use under which the monitor marks the FirePass system up. As an example, a setting of 95 percent means that the monitor marks the FirePass system up until 95 percent of licensed connections are in use. When the number of in-use licensed connections exceeds 95 percent, the monitor marks the FirePass system down The default value is 95.
User Name and Password
If there is no password security, you must use blank strings [""] for the Username and Password settings.
Alias Address and Alias Service Port
The Alias Address setting specifies the destination IP address that the monitor checks, with the default value * All Addresses. For more information, see Chapter 12, Configuring Monitors.
Using an FTP type of monitor, you can monitor File Transfer Protocol (FTP) traffic. A monitor of this type attempts to download a specified file to the /var/tmp directory, and if the file is retrieved, the check is successful. Note that once the file has been successfully downloaded, the BIG-IP system does not save it.
An FTP monitor specifies a user name, a password, and a full path to the file to be downloaded.
Figure 12.14 shows the settings and default values of an FTP-type monitor.
Name my_ftp
Type FTP
Mode Passive
Alias Address * All Addresses
Alias Service Port * All Ports
With an IMAP type of monitor, you can check the status of Internet Message Access Protocol (IMAP) traffic. An IMAP monitor is essentially a POP3 type of monitor with the addition of the Folder setting. The check is successful if the monitor is able to log into a server and open the specified mail folder.
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
Figure 12.15 shows the settings and default values of an IMAP-type monitor.
Name my_imap
Type IMAP
Folder INBOX
Alias Address * All Addresses
Alias Service Port * All Ports
Note: Servers to be checked by an IMAP monitor typically require special configuration to maintain a high level of security, while also allowing for monitor authentication.
An LDAP type of monitor checks the status of Lightweight Directory Access Protocol (LDAP) servers. The LDAP protocol implements standard X.500 for email directory consolidation. A check is successful if entries are returned for the base and filter specified. An LDAP monitor requires a user name, a password, and base and filter strings. Figure 12.16 shows the settings and default values of an LDAP-type monitor.
Name my_ldap
Type LDAP
Alias Address * All Addresses
Alias Service Port * All Ports
The User Name setting specifies a distinguished name, that is, an LDAP-format user name.
The Base setting specifies the starting place in the LDAP hierarchy from which to begin the query.
The Filter setting specifies an LDAP-format key of the search item.
The Security setting specifies the security protocol to be used. Acceptable values are SSL, TLS, or None.
The Mandatory Attributes setting affects the way that the system conducts the filter search. When the value is No, the system performs a one-level search for attributes, and if the search returns no attributes, the node is reported as up. When the value is Yes, the system performs a subtree search, and if the search returns no attributes, the node is not reported as up.
For an LDAP monitor to work properly, the BIG-IP system must be able to perform a reverse DNS lookup on the address of the LDAP or LDAPS node. This reverse lookup allows the BIG-IP system to check the host name of the node's address when it verifies the SSL certificate. An external DNS server does not work with this type of monitor
The reverse DNS lookup requirement applies to both LDAP and LDAPS nodes, even though LDAP does not require the use of an SSL certificate.
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
You use an MSSQL type of monitor to perform service checks on Microsoft® SQL Server-based services such as Microsoft® SQL Server versions 6.5 and 7.0.
If you receive a message that the connection was refused, verify that the IP address and port number or service are correct. If you are still having login trouble, see Troubleshooting MSSQL logins.
The remainder of this section on MSSQL monitors describes prerequisite tasks, the default monitor settings, and troubleshooting tips.
Before using an MSSQL-type monitor, you must download a set of JDBC JavaTM Archive (JAR) files and install them on the BIG-IP system. For more information, see Appendix A, Additional Monitor Considerations.
Figure 12.17 shows the settings and default settings of an MSSQL-type monitor.
Name my_mssql
Type mssql
Alias Address * All Addresses
Alias Service Port * All Ports
In an MSSQL-type monitor, the Database setting specifies the name of the data source on the Microsoft® SQL-based server. Examples are sales and hr.
The Send String setting is optional and specifies a SQL query statement that the BIG-IP system should send to the server. Examples are SELECT * FROM sales and SELECT FirstName, LastName From Employees. If you configure the Send String setting, you can also configure these settings:
Receive String
The Receive String setting is an optional parameter that specifies the value expected to be returned for the row and column specified with the Receive Row and Receive Column settings. An example of a Receive String value is ALAN SMITH. You can only configure this setting when you configure the Send String setting.
Receive Row
The Receive Row setting is optional, and is useful only if the Receive String setting is specified. This setting specifies the row in the returned table that contains the Receive String value. You can only configure this setting when you configure the Send String setting.
Receive Column
The Receive Column setting is optional and is useful only if the Receive String setting is specified. This setting specifies the column in the returned table that contains the Receive String value. You can only configure this setting when you configure the Send String setting.
Debug
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
If an MSSQL monitor cannot log in to the server, and you have checked that the specified IP address and port number or service are correct, try the following:
Verify that you can log in using another tool.
For example, the server program Microsoft Windows® NT® SQL Server version 6.5 includes a client program named ISQL/w. This client program performs simple logins to SQL servers. Use this program to test whether you can log in to the server using the ISQL/w program.
Add login accounts using the Microsoft® SQL Enterprise Manager.
On the Microsoft® SQL Server, you can run the SQL Enterprise Manager to add login accounts. When first entering the SQL Enterprise Manager, you may be prompted for the SQL server that you want to manage.

You can register servers by entering the machine name, user name, and password. If these names are correct, the server becomes registered and you are then able to click an icon for the server. When you expand the subtree for the server, there is an icon for login accounts.

Beneath this subtree, you can find the SQL logins. Here, you can change passwords or add new logins by right-clicking the Logins icon. Click this icon to access the Add login option. After you open this option, type the user name and password for the new login, as well as which databases the login is allowed to access. You must grant the test account access to the database you specify in the EAV configuration.
You use an NNTP type of monitor to check the status of Usenet News traffic. The check is successful if the monitor retrieves a newsgroup identification line from the server. An NNTP monitor requires a newsgroup name (for example, alt.cars.mercedes) and, if necessary, a user name and password.
Figure 12.18 shows the settings and default values of an NNTP-type monitor.
Name my_nntp
Type NNTP
Alias Address * All Addresses
Alias Service Port * All Ports
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
With an Oracle type of monitor, you can check the status of an Oracle database server. The check is successful if the monitor is able to connect to the server, log in as the indicated user, and log out.
Figure 12.19 shows the settings and default values of an Oracle-type monitor.
Name my_oracle
Type Oracle
Alias Address * All Addresses
Alias Service Port * All Ports
The Send String setting specifies a SQL statement that the BIG-IP system should send to the Oracle server. An example is SELECT * FROM sales.
The Receive String setting is an optional parameter that specifies the value expected to be returned for a specific row and column of the table that the Send String setting retrieved. An example of a Receive String value is SMITH.
In an Oracle type of monitor, the Database setting specifies the name of the data source on the Oracle server. Examples are sales and hr.
The Receive Row setting is optional, and is useful only if the Receive String setting is specified. This setting specifies the row in the returned table that contains the Receive String value.
The Receive Column setting is optional and is useful only if the Receive String setting is specified. This setting specifies the column in the returned table that contains the Receive String value.
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
A POP3 type of monitor checks the status of Post Office Protocol (POP) traffic. The check is successful if the monitor is able to connect to the server, log in as the indicated user, and log out. A POP3 monitor requires a user name and password.
Figure 12.20 shows the settings and default values of a POP3-type monitor
Name my_pop3
Type POP3
Alias Address * All Addresses
Alias Service Port * All Ports
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
Using a RADIUS type of monitor, you can check the status of Remote Access Dial-in User Service (RADIUS) servers. The check is successful if the server authenticates the requesting user. A RADIUS monitor requires a user name, a password, and a shared secret string for the code number.
Note: Servers to be checked by a RADIUS monitor typically require special configuration to maintain a high level of security while also allowing for monitor authentication.
Figure 12.21 shows the settings and default values of a RADIUS-type monitor.
Name my_radius
Type RADIUS
Alias Address * All Addresses
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
A Real Server type of monitor checks the performance of a node that is running the RealSystem Server data collection agent. The monitor then dynamically load balances traffic accordingly. Performance monitors are generally used with dynamic ratio load balancing. For more information on performance monitors and dynamic ratio load balancing, see Appendix A, Additional Monitor Considerations.
The BIG-IP system provides a pre-configured Real Server monitor named real_server. Figure 12.22 shows the settings and default values of the real_server monitor.
Figure 12.22 The real_server pre-configured monitor
Name real_server
Type Real Server
Method GET
Command GetServerStats
Metrics ServerBandwidth:1.5, CPUPercentUsage, MemoryUsage, TotalClientCount
Agent Mozilla/4.0 (compatible: MSIE 5.0; Windows NT)
Like all pre-configured monitors, the real_server monitor is not user-modifiable. However, if you want to modify the Metrics setting, you can create a custom Real Server monitor, to which you can add metrics and modify metric values.
Note: When creating a custom Real Server monitor, you cannot modify the values of the Method, Command, and Agent settings.
Table 12.3 shows the complete set of server-specific metrics and metric setting default values that apply to the GetServerStats command.
The metric coefficient is a factor determining how heavily the metrics value counts in the overall ratio weight calculation. The metric threshold is the highest value allowed for the metric if the metric is to have any weight at all. To understand how to use these values, it is necessary to understand how the overall ratio weight is calculated. The overall ratio weight is the sum of relative weights calculated for each metric. The relative weights, in turn, are based on three factors:
You can see that the higher the coefficient, the greater the relative weight calculated for the metric. Similarly, the higher the threshold, the greater the relative weight calculated for any metric value that is less than the threshold. (When the value reaches the threshold, the weight goes to zero.)
Note that the default coefficient and default threshold values shown in Table 12.3 are metric defaults, not monitor defaults. The monitor defaults take precedence over the metric defaults, just as user-specified values in the custom real_server monitor take precedence over the monitor defaults. For example, the monitor shown specifies a coefficient value of 1.5 for ServerBandwidth and no value for the other metrics. This means that the monitor uses the monitor default of 1.5 for the ServerBandwidth coefficient and the metric default of 1 for the coefficients of all other metrics. However, if a custom monitor my_real_server were configured specifying 2.0 as the ServerBandwidth coefficient, this user-specified value would override the monitor default.
Metric coefficient and threshold are the only non-monitor defaults. If a metric not in the monitor is to be added to the custom monitor, it must be added to the list of metrics for the Metrics setting. The syntax for specifying non-default coefficient or threshold values is:
Through the RPC monitor, you can use the BIG-IP system to check the availability of specific programs that reside on a Remote Procedure Call (RPC) server. This monitor uses the rpcinfo command to query the RPC server and verify the availability of a given program.
The RPC monitor contains two unique settings: program and version. The program setting specifies the program or application which the monitor needs to verify is available. The version setting is an optional setting that specifies an exact version number of that program. If you do not specify a version number, the monitor uses the rpcinfo command to verify that at least one version of the program is available. In addition, you can use the mode option of the RPC monitor to verify the availability of an RPC server using either TCP or UDP.
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
The resource that this monitor checks is considered available if it responds with a ready and waiting statement to the monitor query.
Figure 12.26 shows the settings and default values of an RPC-type monitor.
Name my_rpc_monitor
Type RPC
Mode TCP
Program <name>
Alias Address * All Addresses
Alias Service Port * All Ports
If your network employs IBM® Group Workload Managers for some of your network resources, you can employ the SASP monitor to verify the availability of these resources. This monitor uses the Server/Application State Protocol (SASP) to communicate with the Group Workload Manager. This monitor queries the Group Workload Manager for information on the current weights of each managed resource. These weights determine which resource currently provides the best response time. When the monitor receives this information from the Group Workload Manager (GWM), it configures the dynamic ratio option for the resources, allowing the BIG-IP system to select the most appropriate resource to respond to a connection request.
The SASP monitor contains several unique settings: GWM Interval, GWM Address, GWM Service Port and GWM Protocol. The GWM Interval option determines the frequency at which the monitor queries the GWM. You can either set this option to Automatic, which instructs the monitor to use the interval GWM recommends; or you can select Specify, which allows you to supply an interval. If you select Specify, you can assign an interval between 10 and 600 seconds.
The GWM Address option specifies the IP address of the Group Workload Manager. The GWM Service Port option specifies the port through which the SASP monitor communicates with the Group Workload Manager. Lastly, the GWM Protocol option allows you to specify which protocol the monitor uses: either TCP or UDP.
Note: When you assign a SASP monitor, the monitor initially marks the resources as down. This change in status occurs because the GWM might not yet have information pertaining to its resources. As soon as the monitor receives the results of its query, it changes the status as needed. In most configurations, the monitor receives these results within a few seconds.
Figure 12.26 shows the settings and default values of an SASP-type monitor.
Name my_sasp_monitor
Type SASP
Interval Automatic
GWM Address 10.10.5.23
You use the Scripted type of monitor to generate a simple script that reads a file that you create. The file contains send and expect strings to specify lines that you want to send or that you expect to receive. For example, Figure 12.25 shows a sample file that you could create, which specifies a simple SMTP sequence. Note that the lines of the file are always read in the sequence specified.
Using a Scripted monitor, you can then generate a script that acts on the above file. When the Scripted monitor script reads this file, the script examines each line, and if the line has no double quotes, the line is sent or expected to be received as is. If the line is surrounded by quotation marks, the script strips off the quotation marks, and examines the line for escape characters, treating them accordingly.
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
Figure 12.26 shows the settings and default values of a Scripted-type monitor.
Name my_scripted_monitor
Type Scripted
Filename <filename>
Alias Address * All Addresses
Alias Service Port * All Ports
You use a SIP type of monitor to check the status of SIP Call-ID services. This monitor type uses UDP to issue a request to a server device. The request is designed to identify the options that the server device supports. If the proper request is returned, the device is considered to be up and responding to commands.
Figure 12.27 shows the settings and default values of a SIP-type monitor.
Name my_sip
Type SIP
Mode UDP
Alias Address * All Addresses
Alias Service Port * All Ports
Possible values for the Mode setting are TCP and UDP.
Possible values for the Additional Accepted Status Codes setting are Any, None, and Status Code List. The Status Code List setting specifies one or more status codes, in addition to status code 200, that are acceptable in order to indicate an up status. Multiple status codes should be separated by spaces. Specifying an asterisk (*) indicates that all status codes are acceptable.
Possible values for the Debug setting are No and Yes. The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
With the SMB monitor, you can use the BIG-IP system to verify the availability of an SMB/CIFS (Server Message Block/Common Internet File System) server. You can employ this monitor to either check the availability of the server as a whole, the availability of a specific service on the server, or the availability of a specific file used by a service.
SMB/CIFS Server
Specifies the NetBIOS name of the SMB/CIFS server for which the monitor checks for availability. You must specify a server for this monitor to function.
Service Name
Specifies a specific service on the SMB/CIFS for which you want to verify availability. You are not required to specify a service name.
Path/Filename
Specifies a specific file associated with a service. The monitor uses the relative path to the service itself when attempting to locate the file. You are not required to specify a value for this option; however, if you elect to use this option you must also specify a service using the service name option.
Debug
Specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
If you only specify the server using the SMB/CIFS server option, leaving the service name and path/filename options empty, the monitor attempts to retrieve a list of available services from the SMB/CIFS server. If the monitor acquires a list, it marks the server as available.
Figure 12.28 shows the settings and default values of a SMB-type monitor.
Name my_smb
Type SMB
User Name <name>
Password <password>
Path/Filename <filename and path>
Alias Address * All Addresses
Alias Service Port * All Ports
An SMTP type of monitor checks the status of Simple Mail Transport Protocol (SMTP) servers. This monitor type is an extremely basic monitor that checks only that the server is up and responding to commands. The check is successful if the mail server responds to the standard SMTP HELO and QUIT commands. An SMTP-type monitor requires a domain name.
Figure 12.29 shows the settings and default values of an SMTP-type monitor.
Name my_smtp
Type SMTP
Alias Address * All Addresses
Alias Service Port * All Ports
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
With an SNMP DCA type of monitor, you can check the performance of a server running an SNMP agent such as UC Davis, for the purpose of load balancing traffic to that server. With this monitor you can define ratio weights for CPU, memory, and disk use.
Performance monitors are generally used with dynamic ratio load balancing. For more information on performance monitors and dynamic ratio load balancing, see Appendix A, Additional Monitor Considerations.
The BIG-IP system provides a pre-configured SNMP DCA monitor named snmp_dca. Figure 12.30 shows the settings and values of the snmp_dca pre-configured monitor.
Figure 12.30 The snmp_dca pre-configured monitor
Name snmp_dca
Type SNMP DCA
Community Public
Pre-configured monitors are not user-modifiable. Thus, if you want to change the values for the SNMP DCA monitor settings, you must create an SNMP DCA-type custom monitor. Possible values for the Version setting are v1, v2c, and Other.
The Agent Type setting identifies the group of SNMP objects that the BIG-IP system uses to determine server health. Possible values for the Agent Type setting are:
UCD
This agent type corresponds to the UCD MIB. The group of objects based on the UCD MIB provides CPU load that is averaged over the up time of the server.
WIN2000
This agent type is based on RFC 2790, the Host Resources MIB. The group of objects based on the Host Resources MIB provides CPU load that is averaged over one minute instead of over the up time of the server. This agent type works well for all server platforms and is therefore the recommended agent type.
Other
This is an agent type that you specify.
Table 12.4 shows the SNMP objects corresponding to the UCD and WIN2000 agent types.
When configuring an SNMP DCA custom monitor, you can use the default CPU, memory, and disk coefficient and threshold values specified in the monitors, or you can change the default values. Optionally, you can specify coefficient and threshold values for gathering other types of data. Note that if the monitor you are configuring is for a type of SNMP agent other than UC Davis, you must specify the agent type, such as Win2000.
To understand how to use the coefficient and threshold values, it is necessary to understand how the overall ratio weight is calculated. The overall ratio weight is the sum of relative weights calculated for each metric. The relative weights, in turn, are based on three factors:
You can see that the higher the coefficient, the greater the relative weight calculated for the metric. Similarly, the higher the threshold, the greater the relative weight calculated for any metric value that is less than the threshold. (When the value reaches the threshold, the weight goes to zero.)
You use an SNMP DCA Base type of monitor to check the performance of servers that are running an SNMP agent, such as UC Davis. However, you should use this monitor only when you want the load balancing destination to be based solely on user data, and not CPU, memory or disk use.
Figure 12.31 shows the settings and default values of an SNMP DCA Base type of monitor.
Figure 12.31 An SNMP DCA-type custom monitor with default values
Name my_snmp_dca_base
Type snmp_dca_base
Community Public
Performance monitors are generally used with dynamic ratio load balancing. For more information on performance monitors and dynamic ratio load balancing, see Appendix A, Additional Monitor Considerations.
A SOAP monitor tests a web service based on the Simple Object Access protocol (SOAP). More specifically, the monitor submits a request to a SOAP-based web service, and optionally, verifies a return value or fault. Figure 12.32 shows the settings and default values of a SOAP-type monitor.
Name my_soap
Type soap
Protocol" HTTP
Method ""
Parameter Name ""
Alias Address * All Addresses
Alias Service Port * All Ports
Possible values for the Protocol setting are HTTP and HTTPS.
Possible values for the Parameter Type setting are: bool, int, long, and string.
Possible values for the Return Type setting are: bool, int, short, long, float, double, and string.
Possible values for the Expect Fault setting are No and Yes.
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
You use a UDP type of monitor when the system is sending User Datagram Protocol (UDP) packets. Designed to check the status of a UDP service, a UDP-type monitor sends one or more UDP packets to a target pool, pool member, or node.
Figure 12.33 shows the settings and default values of a UDP-type monitor. As shown in this figure, the value in seconds of the Timeout Packets setting should be lower than the value of the Interval setting.
Name my_udp
Send String default send string
Alias Address * All Addresses
Alias Service Port * All Ports
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
When using a UDP-type monitor to monitor a pool, pool member, or node, you must also enable another monitor type, such as ICMP, to monitor the pool, pool member, or node. Until both a UDP-type monitor and another type of monitor to report the status of the UDP service as up, the UDP service receives no traffic. See Table 12.5 for details.
And another monitor reports status as
You use a WAP monitor to monitor Wireless Application Protocol (WAP) servers. The common usage for the WAP monitor is to specify the Send String and Receive String settings only. The WAP monitor functions by requesting a URL (the Send String setting) and finding the string in the Receive String setting somewhere in the data returned by the URL response. Figure 12.34 shows the settings and default values of a WAP-type monitor.
Name my_wap
Alias Address * All Addresses
Alias Service Port * All Ports
The Secret setting is the RADIUS secret, a string known to both the client and the RADIUS server, and is used in computing the MD5 hash.
The Accounting Node setting specifies the RADIUS node. If this a null string and RADIUS accounting has been requested (accounting port is non-zero), then the WAP server node is assumed to also be the RADIUS node.
If set to non-zero, the Accounting Port setting requests RADIUS accounting and uses the specified port.
The Server ID setting specifies the RADIUS NAS-ID of the requesting server (that is, the BIG-IP system). It is a string used as an alias for the FQDN. See the section on testing WAP_monitor just below.
The Call ID setting is an identifier similar to a telephone number, that is, a string of numeric characters. For testing purposes, this value is usually a string of eleven characters.
The Session ID setting is a RADIUS session ID, used to identify this session. This is an arbitrary numeric character string, often something like 01234567.
The Framed Address setting is a RADIUS framed IP address. The setting has no special use and is usually specified simply as 1.1.1.1.
RADIUS accounting is optional. To implement RADIUS accounting, you must set the accounting port to a non-zero value. If you set the Accounting Port setting to a non-zero value, then the monitor assumes that RADIUS accounting is needed, and an accounting request is sent to the specified accounting node and port to start accounting. This is done before the URL is requested. After the successful retrieval of the URL with the correct data, an accounting request is sent to stop accounting.
The Debug setting specifies whether the monitor sends error messages and additional information to a log file created and labeled specifically for the monitor. Possible values for the Debug setting are No and Yes. The default setting is No, which specifies that the system does not redirect error messages and additional information related to this monitor. The Yes setting specifies that the system redirects error messages and additional information to the /var/log/<monitor_type>_<ip_address>.<port>.log file. You can use the log information to help diagnose and troubleshoot unsuccessful health checks.
A WMI type of monitor checks the performance of a node that is running the Windows Management Infrastructure (WMI) data collection agent and then dynamically load balances traffic accordingly.
You generally use performance monitors such as a WMI monitor with dynamic ratio load balancing. For more information on performance monitors and dynamic ratio load balancing, see Appendix A, Additional Monitor Considerations.
Figure 12.35 shows the settings and default values of a WMI-type monitor.
Name my_wmi
Type wmi
Method POST
URL /scripts/f5Isapi.dll
Command GetCPUInfo, GetDiskInfo, GetOSInfo
Metrics LoadPercentage, DiskUsage, PhysicalMemoryUsage:1.5, VirtualMemoryUsage:2.0
Agent Mozilla/4.0 (compatible: MSIE 5.0; Windows NT)
Post RespFormat=HTML
Note that when creating a custom WMI monitor, the only default values that you are required to change are the null values for user name and password. Also note that you cannot change the value of the Method setting.
Table 12.6 shows the complete set of commands and metrics that you can specify with the Command and Metrics settings. Also shown are the default metric values.
Default Coefficient
When managing existing monitors, you can display or delete them, or you can enable and disable an instance of a monitor. Prior to deleting a monitor, you must remove all existing monitor associations.
Note: You can manage only those monitors that you have permission to manage, based on your user role and partition access assignment.
1.
On the Main tab, expand Local Traffic, and click Monitors.
The Monitors screen opens.
2.
Click a monitor name.
This displays the monitor settings and their values.
1.
On the Main tab, expand Local Traffic, and click Monitors.
The Monitors screen opens.
3.
Click Delete.
A confirmation message appears.
4.
Click Delete.
1.
On the Main tab, expand Local Traffic, and click Monitors.
The Monitors screen opens.
3.
On the menu bar, click Instances.
This lists any existing monitor instances.
5.
Click Enable or Disable.
6.
Click Update.
Note: Be aware that because instances of monitors are not partitioned objects, a user can sometimes enable or disable an instance of a monitor without having permission to manage the associated pool or pool member. For example, a user with a Manager role, who can access partition AppA only, can enable or disable monitor instances for a pool that resides in AppB.
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